See this thread for more details:
My guess is that you are using an unsupported GeForce card and either Windows or NVIDIA has done an automatic driver updated that you are unaware of. Most in that thread say the solution is to install the latest driver, go back to an older driver, or turn off an anti-aliasing setting. See the thread for details.
Also, make sure you search the forum before posting. This same type of issue has been posted about 10 times in the last few weeks so it will lead to a quicker solution by searching.
I hope this helps,
thank you so much for your help ! It was a failiure in the OpenGL-settings and SW is now running again !
I promise, I´ll search the forum before I create a new question